title: Oral administration of heat-killed Lactobacillus gasseri OLL2809 reduces cedar pollen antigen-induced peritoneal eosinophilia in Mice.
abstract: BACKGROUND
  Lactobacillus gasseri OLL2809 strongly stimulates the production of interleukin (IL)-12 (p70) by innate immune cells. Thus, it is expected to ameliorate allergic diseases. We investigated whether the oral administration of heat-killed L. gasseri OLL2809 suppressed eosinophilia in cedar pollen antigen-challenged mice.
  
  
  METHODS
  BALB/c mice sensitized with Japanese cedar pollen extract were intraperitoneally challenged with the same extract. The mice were orally given heat-killed L. gasseri OLL2809 at doses of 0.5, 1, or 2mg/day throughout the experimental period (21 d). After 24 hours of the challenge, the eosinophil number and cytokine levels in the peritoneal lavage fluid and the serum antigen-specific IgG levels were determined.
  
  
  RESULTS
  On administering varying amounts of heat-killed L. gasseri OLL2809, the number of eosinophils among the total number of cells was significantly reduced in all groups. In addition, the eosinophil number significantly decreased, and the eosinophil-suppression rate significantly increased by 44% in the 2-mg group. Although the serum immunoglobulin (Ig) G2a and IgG1 levels were not affected, the IgG2a/IgG1 ratio increased significantly in the 2-mg group compared with that of the control group. Furthermore, the administration of heat-killed L. gasseri OLL2809 resulted in the induction of IL-2 and reduction in granulocyte-macrophage colony-stimulating factor levels in peritoneal lavage fluid.
  
  
  CONCLUSIONS
  We demonstrated that the oral administration of heat-killed L. gasseri OLL2809 suppresses eosinophilia via the modulation of Th1/Th2 balance. These observations suggested that heat-killed L. gasseri OLL2809 might potentially ameliorate the increased number of eosinophils in patients with Japanese cedar pollinosis.
authors.affiliation: Division of Research and Development, Meiji Dairies Corporation, Kanagawa, Japan. toshihiro_sashihara@meiji-milk.com
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sashihara
authors.forename: Shuji
authors.initials: S
authors.lastname: Ikegami
authors.forename: Natsuko
authors.initials: N
authors.lastname: Sueki
authors.forename: Taketo
authors.initials: T
authors.lastname: Yamaji
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Kino
authors.forename: Naoki
authors.initials: N
authors.lastname: Taketomo
authors.forename: Minoru
authors.initials: M
authors.lastname: Gotoh
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Okubo
mesh_terms: D000284:Administration, Oral; D000818:Animals; D052179:Antigens, Plant / Q000008:administration & dosage / Q000276:immunology*; D028203:Cedrus / Q000276:immunology*; D002452:Cell Count; D004802:Eosinophilia / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006358:Hot Temperature; D007114:Immunization; D007136:Immunoglobulins / Q000097:blood; D007165:Immunosuppression Therapy; D007376:Interleukin-2 / Q000378:metabolism; D007778:Lactobacillus / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010537:Peritoneum / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D011058:Pollen / Q000276:immunology
chemical_list: D052179:Antigens, Plant; D007136:Immunoglobulins; D007376:Interleukin-2; D016178:Granulocyte-Macrophage Colony-Stimulating Factor